Propeller control mechanism



Patented June 8,. 1943 2,321,026 PROPELLER CONTROL MECHANISM John'HaysHammond, 'Jr., Gloucester, Mass. Application October 10, 1941, SerialNo. 414,489

Claims.

This invention relates to variable pitch propellers and morespecifically to means for automatically varying the pitch of a propellerso as to maintain the speed of a vessel constant under varyingconditions of wind and weather.

The invention further relates to distance indicating means operated bythe motion of the vessel through the water which directly controls meansfor varying the pitch of the propeller blades in such a way that thepower supplied to the propeller is varied so as to maintain the vesselat a predetermined speed.

The invention also provides means for varying the rate of change ofpitch of the propeller blades in accordance with the rate of change ofthe vessel's speed, thus preventing rapid changes of pitch of thepropeller blades which might cause I stood by referring to the followingdescription,

taken in connection with the accompanying drawings forming a partthereof, in which Figure 1 illustrates diagrammatically the system asapplied to the driving mechanism of a marine vessel;

Figure 2 is a vertical section taken on line 2-2 of Figure 1; and

Figure 3 is a horizontal section taken on line 3-3 of Figure 2.

Like reference characters denote like parts in the several figures ofthe drawings.

In the following description and in the claims parts will be identifiedby specific names for convenience, but they are intended to be asgeneric in their application to similar parts as the art will permit.

Referring to the accompanying'drawings, and more particularly to Figure1, the hull of a marine vessel is indicated at It. This vessel is drivenby means of a propeller i2 which is provided with adjustable blades i3.The propeller I2 is attached to the end of a hollow shaft which passesthrough an outboard bearing IS The shaft I5 is driven by a prime moverably provided with a governor, not shown, for' maintaining a constantspeed of rotation.

The blades 13 are connected to a variable pitch mechanism i8 which maybe of any well known and standard construction such as that manufacturedby the Escher-Wyss Company of Zurich, Switzerland, the detailsof whichform no part of the present invention and are accordingly notspecifically set forth herein. This mechanism, in general, comprises arod i9 slidable longitudinally within the shaft l5 and connected tocontrol the pitch of the blades Ill. The rod i9 is actuated by a piston21 in a fluid pressure cylinder 21a. Fluid for actuating the piston 21is supplied by a pump 26 through a control valve 25 and a distributionvalve 25a which communicates with the cylinder 21a through ducts, notshown, in the shaft IS. A motor 2! rotates a worm 22 which operates tomove the upper end of a floating lever 23, which, in turn, is pivoted tothe end of a valve rod 24 which controls the valve 25. The piston 21 isconnected by a rod 28 to a collar 29 which is slidably mounted on theshaft l5 and engages the lower end of the lever 23-so that the positionof this end of the lever corresponds to the pitch of theblades Ill.

The upper end of the lever 23 is connected by a wire to an indicator 3|which shows the pitch at which the blades I3 are set. Stops 32 areprovided for limiting the maximum and minimum pitch of the blades l3.The fluid pump 26 is driven either-by a motor 33 or a belt 35 from theshaft l5. A reservoir 36 and a supply tank 31 are provided for thenecessary fluid.

It is to be understood that other pitch control devices may be employedin place of that referred to above, for varying the pitch of thepropeller blades l3 in response to actuation of the motor illustrationonly.

. A distance recorder- 39 is provided which includes frame 40 in whichis mounted a standard type of ships log mechanism 4| (Figure 2) which isdriven by means of a cable 42, which passes outboard thru a stufiing box43 mounted in the hull H. The usual ships log propeller, not shown, isattached to the end of the cable 42 and causes this cable to rotate anamount proportional to the distance travelled by the vessel.

The ships log mechanism M, which is of well known and standardconstruction and which need not be more fully described herein, isprovided with a shaft 45 which is rotated an amount proportional to thedistance travelled by which may be of any desired type and is preferthevessel. For example the normal speed of the A particular type is shownfor purposes of vessel may be 24 knots per hour and the shaft 85 maymake one revolution in twenty minutes, so that one revolution of theshaft 45 would represent a distance of eight knots.

Mounted on the log mechanism 4| is a subframe 46 which is provided witha lug. 41 to which is pivoted a yoke shaped arm 48. Pivotally connectedto the arm 88 is the plunger of a solenoid 58, which is mounted on theframe 96. A pin I is mounted on the top of the log mechanism 8! and actsto limit the downward motion of the arm 48. Pivotally mounted at the endof the yoke shaped arm 98 is a collar 52 which loosely surrounds acylindrical clutch member 53, which is secured to the shaft 85.

Rotatably mounted in the frame 88 and subframe 86 is a shaft 55 on thelower end of which a collar 58 is slidably but not rotatably mounted.The collar 56 is provided with a groove 51 which is loosely engaged bytwo pins 58 mounted in the end of a second yoke shaped arm 59, which ispivoted to a lug 68 secured to the frame 46. Pivotally connected to thearm 59 is the plunger of a solenoid 6i, which is mounted on the subframe46.

Surrounding the shaft 55 and secured to the sub-frame 46 is a thrustball bearing 62 between which and the collar 56 is mounted a compressionspring 63. Secured to the shaft 55 is a gear 65 which meshes with a rack66, which forms part of the core of a solenoid 61. The rack 86 isslidably mounted in a bracket 58 and is provided on its end with aprojection 69 forming a stop to limit the'motion of the rack. Secured tothe upper end of the shaft 55 is an arm 18.

Mounted on the base of the frame 48 is a driving mechanism II, which isprovided with a shaft I2, which may be driven at a constant speed, forexample, one revolution in twenty minutes. Attached to the shaft I2 aretwo commutators I3 and 14 which are made of insulating material and areprovided with two contact segments and I6 respectively. Engaging thecommutator 73 are threecontacts I1, 18 and 19. The contact I! isconnected to one side of the winding of the solenoid 58, the other sideof which is connected thru a'battery 88 to the contact '18. The contactI9 is connected to one side of the windings of the solenoids 6| and 61the other sides of which are connected to the battery 88.

The commutator I4 is engaged by two contacts 8| and 82 which areconnected to two terminals 85 and 86. The terminal 85 is connected to acontact 81 which is mounted on but insulated from the arm 18, and theterminal 86 is connected to the center point of a three position switch88 (Figure 1). The upper and lower points of the switch 88 are connectedrespectively by two conductors 98 and 9| to the reversing windings ofthe motor 2I. The common lead of the reversing windings of the motor 2|is connected to one side of a battery 92 the other side of which isconnected to the blade of the switch 88.

The contact 81 selectively engages six segments 93-98 which are mountedon but insulated from an arc-shaped member 99, which is slidably mountedin two brackets I88 and NI mounted on the frame 48. A clamping screw I82is provided in the bracket I8I for holding the member 99 in any desiredposition. A pointer I83 is secured to the member 89 and registers. witha scale I85 which is attached to the frame 48 and which may be graduatedin knots.

The segments 93 and 98 are connected by flexible conductors to theconductors 9| and 98 respectively. The segments 96 and 95 are connectedby flexible conductors to two resistors I85 and I8'I, the other ends ofwhich are connected nected to the conductor 98.

Operation In the operation of the form of the invention shown the pitchof the blades I3 is set at the normal operating angle for the speed atwhich it is desired to operate the vessel, which for example may be 24knots; The setting of the propeller blades I3 is accomplished by movingthe blade of the switch 88 into the upper or lower position which willcause the motor 2i to move the upper end of the lever 23 to the left orright to increase or decrease the pitch in a well known manner, theangle of pitch being indicated by the pointer of the indicator 3|.

The vessel is then brought up to the desired speed in this case 24 knotsper hour and the member 99 is moved until the pointer I83 indicates 24knots on the scale I85. The screw I82 is then tightened holding themember 99 and segments 9398 in the proper position for this speed.

The mechanism operates in cycles of, for example, 20 minutes and isshown at the start of one of these cycles. The arm I8 and contact 81 arein the zero position and have just been clutched to th shaft 45 of theship's log mechanism 4|. As the vessel proceeds through the water thecable 42 is rotated in the usual manner by the ships log propeller, notshown, and in turn operates the mechanism 4| which slowly rotates theshaft 45 an amount proportional to the distance the vessel travels. Thismotion is transmitted thru the clutch 53-56 to the shaft 55 which inturn rotates the arm I8 and contact 81 by the same amount.

At the same time the shaft I2 is slowly rotated it to raise the arm 48together with the collar 52.

As the collar 52 moves upward it will engage the collar 56 lifting itout of engagement with the clutch member 53. This will immediately stopthe rotation of the shaft 55 and hold it, together with the arm I0 andcontact 81, in a fixed position.

After the shaft I2 rotates slightly further, for

example, about two degrees more, the segment 16 will engage the contacts8I and 82 which will put the pitch setting mechanism into an operativecondition. If during the 15 minute inte ratin interval the vessel hasmaintainedits speed constant at 24 knots it will have travelled 6 knotsand the shaft 55 will have rotated three-quarters of a revolution in acounterclockwise direction. Under these conditions the contact 81 willcome to rest on the insulation between the segments and 96 and the pitchsetting mechanism will not be operated.

If the conditions under which the vessel is travelling should change,however, such as by encountering a strong head wind or running into aheavy sea and the speed of the vessel be thereby diminished the logmechanism II will not have rotated the shaft 45 by a full three-quartersof a revolution during the stated interval, so that the contact 81 willengage the segment 96 instead of the insulation between the segments 95and 96.

This will close a circuit from the battery 92 thru pitch. This willcause more power to be transmitted from the prime mover 20, the R. P. M.

being maintained constant by means of the governor, therebyincreasingthe speed of the vessel.

This slow increase of propeller pitch continues for a two minuteoperating interval during which the shaft 12 rotates thru about 36degrees. The circuit is then broken between the contacts 8| and 82, thusputting the pitch setting mechanism into an inoperative condition. Afterthe shaft 12 has made a further revolution of, for example, about twodegrees, the segment 15 will engage the contact I9 closing a circuitfrom the battery 80 to Ifthe vessel should increase its speed due to afollowing wind or other favorable conditions, the shaft 55 together withthe contact 81 would make more than three-quarters of a revolution inthe fifteen minute integrating interval. Under these conditions thecontact 81 would engage one of the segments 95, 94, or 93 and thereverse action would take place, thus causing a decrease of propellerpitch during the two minute operating period. The speed of operation ofthe pitch changing mechanism would vary with the in-,

crease of speed during the fifteen minute integrating period in a mannersimilar to that already described.

In this way the pitch of the propeller blades I3 is varied every fifteenminutes an amount proportional to the integrated variation of speed fromthe two solenoids BI and 51. When the solenoid BI is energized it willraise the collar 55 causing it to disengage the collar 52, so that theshaft 55, arm lll'and contact 81 will be free from both the clutchmember 53 and the collar 52. When the solenoid GT is energized it willcause the rack 56 to be moved to the left, which will rotate the gear 55and shaft 55 in a clockwise direction until the projection 59 engagesthe bracket 68. When this has occurred the arm 10 and contact 81 will bereset in their zero position as shown in Figure 1.v

After the shaft 12 has rotated a further 46 degrees, the segment 15 willdisengage the contact Tl, thus opening the circuit to the solenoid 50.This will allow the arm 48 and collar 52 to move normal during thisperiod. The propeller pitch is thus varied to cause the propeller todraw the required power from the prime mover 20 to maintain the speed ofthe vessel constant. The amount that the pitch is changed during the twominute 'operatinginterval will depend upon the change of speed of thevessel during the preceding fifteen minute period. If the change ofpitch during one two minute operating interval does not exactly correctthe condition, a further correction will be made at the end of the nextfifteen minute integrating period. In this way the propeller pitch isgradually corrected for changed average operating conditions and is notcontinually fluctuating due to sporadic changes of the vessels speed.

downward until the arm 48 rests on the pin 5| at which time the top ofthe collar 52 will be below the top of the clutch member 53 as shown inFigure 2.

A further revolution of about four degrees of the shaft 12 will causethe segment 15 to disengage the contact 18, thus breaking the circuit tothe solenoids BI and 61 This will allow the arm 59 and collar 56 to movedownwardly under the action of the spring 53 until the collar 55 engagesthe clutch member 53. This action will connect the shaft to the shaft 55and .will complete the twenty minute cycle of operation. The mechanismis now in the position shown in Figures 1 and 2 and is at the start of anew cycle.

If during the fifteen minute integrating interval the conditions hadbeen more adverse, the contact 81 would have been in engagement with thesegment 91 at the time the pitch setting mechanism was put into theoperative condition. Under these circumstances the resistor H15 would bethrown in the circuit of the motor 2|. As'the resistor I09 haslessresistance than the resistor I08 the motor 2'! would be rotatedfaster thus causing a greater change of pitch in the two A thrown in thecircuit of the motor 2|, so that the pitch changing mechanism would havebeen operated at its maximum speed during the two minute operatingperiod.

It is to be understood that while specific intervals of time and anglesof operation have been referred to in the specification the invention isnot limited thereto but may cover any embodiment that accomplishessubstantially the same result.

Although only a few of the various forms in which this invention may beembodied have been shown herein, it is tobe understood that theinvention is not limited to any specific construction but may beembodied in various forms without departing from the spirit of theinvention or the scope of the appended claims.

What is claimed is:

1. In a system for driving a vessel, a propeller having blades, meanscontrolling the pitchof said blades, means measuring the distancetravelled by said vessel in a predetermined time interval, and meansactuated by said last means, in accordance with the distance travelledduring said predetermined time interval, to actuate said pitch controlmeansin a direction and by an amount dependent upon the direction andamount of variation of distance travelled from a predetermined standardand to cause said pitch control mechanism to changethe pitch of saidblades in a direction and by an amount to compensate for said variationsin the distance travelled, whereby said vessel tends to maintain saidstandard.

2. The system set forth in claim 1 in which the propeller is operated atconstant speed.

3. In a system for driving a vessel, a propeller having blades,meanscontrolling the pitch of said blades, means responsive to the speedof travel of said vessel, an integrating device actuated by said speedcontrol means to integrate the distance travelled over a predeterminedperiod of time, and means controlled by said integrating means toactuate said pitch control means for predetermined intervals of time andat speeds corresponding to variations in the integrated distance from apredetermined standard distance which would be travelled under normal 7conditions of operation.

4. The system set forth in claim 1 in which the distance devicecomprises a ship's log.

5. In a system for driving a vessel, a propeller having blades,means'driving said propeller at a constant speed, pitch control meanscontrollin the pitch of said blades, a ships log having means connectedto designate the distance travelled by said ship, means comparing saiddesignated distance with a predetermined stand- 10 vessel tends tomaintain said standard.

JOHN HAYS HAMMOND, JR.

